Lanell Stella

From a purely scientific angle, tooth color is determined by light reflection on enamel and dentin. When enamel is eroded due to acidic foods, brushing too hard, or age, the underlying dentin (which is naturally yellow or darker) becomes more visible. If bacteria invade and cause necrosis, the internal tissue can appear black. So, black teeth are a visual symptom of multiple possible underlying issues, ranging from surface stains to deep structural damage.